Seaweed has been traditionally harvested in Europe, Asia and the Pacific Islands for thousands of years, and today harvesting seaweed is big international business. Not only are seaweeds harvested for direct consumption of the plant itself, but also for the intriguing and functional chemicals or "natural products" they produce. Many of these compounds have application for human use. Chemicals derived from seaweeds are used in medicines, food and beauty products, and industry. That's right, the ice cream and chocolate milk in your fridge, the lipstick in your makeup bag, and even the toothpaste you brushed your teeth with this morning may all be made with seaweed extracts.

How does seaweed end up in both whipped topping and paint? Most seaweeds are algae -- aquatic plants that lack roots, stems or leaves. Algae are divided into three main types: red, brown and green. From each of these types of algae, scientists have been able to identify and isolate compounds that can make foods creamier and paint thicker. Red and brown algae produce phycocolloids ("phyco" = seaweed, "colloid" = glue) that include agar, alginate and carrageenan. Green algae produce the antioxidant beta carotene which is a precursor to vitamin A.

The use of these compounds in food products took off in the second half of the 20th century as the demand for prepared foods increased. Compounds like carrageenan improve the quality of the food and help to stabilize it, making the item more appealing to consumers. Currently the import and export of seaweed is a $200 billion business, with the United States importing nearly $50 billion worth each year. And as more nations become developed, the need for more prepared foods and pharmaceuticals will increase the demand for seaweed compounds.

To meet this demand, selected marine algae are grown, harvested and processed on large scales around the globe and at home. Even high schools are getting in on the act. Bridgeport Regional Vocational Aquaculture School in Connecticut has been working with Connecticut Sea Grant researcher Dr. Charles Yarish to improve aquaculture techniques for the red alga, nori (see picture above). Students and scientists are cultivating nori next to salmon aquaculture pens. The red algae remove from the water excess nutrients produced by the fish, and in turn use those nutrients to grow.

Who harvests and imports seaweeds? The actvitiy below will help you answer this question.

DATA ACTIVITY

This data activity offers two levels of inquiry (from simpler and less time consuming to more complex and time intensive) and a lab extension activity. Teachers should start with Level 1 below, and continue as appropriate for their students and their prep and lesson time available.

We'll use United Nation's Food & Agriculture Organization (FAO) statistical site to research fishery production of marine algae around the world. A report by TradeDataNet provides charts on countries that import and export algae and the average import prices.

Who Harvests Seaweeds?

What were reported world seaweed harvests in 2001? (Note: We're using 2001 so that we can compare data sets from two different sources). Using the FAO Stats we can investigate the world harvest of seaweeds:

From the Global Production page of FAO’s Fisheries Global Information System (FIGIS online query), start your query with the “Country” tab. Select the “Alphabetical” hierarchy, then “All” at the far right of the page. This will give you a long list of countries. Click the “Select All” button so that you get a result for every country that submitted data to FAO.

For the “Fishing Area” tab, select “Marine Waters.”

For the “Species” tab, select “Aquatic Plants,” click on the box with the + inside to see the different kinds of plants included. Check off “Brown,” “Green,” and “Red” seaweeds.

For the “Time” tab, select 2001.

At the “Display” tab, select “Quantity.”

Then “Submit” and you’ll get the total. Click the “Special Values Explanations” feature just under the page heading to find a legend for the units.

What was the total world harvest of seaweed in 2001? Of brown seaweed? Of green seaweed? Of red seaweed?

To go back and retrieve data on each seaweed group separately, go to the top of the page and click “Modify”.

Then, you can go to the “Species” tab and select just “Brown,” just “Green,” and just “Red” seaweeds to get separate totals for each.

Now, you can compare the total world harvest of all three seaweed types and create a pie chart that compares the 2001 harvest in a graphical way.

Next, let's focus in on the most significant harvests and where they come from. Which countries harvested the most red seaweeds and brown seaweeds in 2001?

At the top of the FAO’s Fisheries Global Information System page, click “Modify.”

At the “Country” tab, select the “Alphabetical” hierarchy, then “All” at the far right of the page. This will give you a long list of countries. Click the “Select All” button so that you get a result for every country that submitted data to FAO.

Under the “Species” tab, select only “Brown seaweed.”

Then, for “Display,” click country and quantity. Submit. This gives you a table of countries and the quantity of brown seaweeds harvested in 2001.

Repeat this, using the “Modify” button, next looking for harvests of the “Red seaweeds."

From your results, make a list of the top six countries in brown seaweed production and in red seaweed production.

For graphing skills opportunities:

With the data you gather, create a histogram for each country with # ton on the Y axis. You could pin the histogram columns on a world map to link the data with geographic locations of seaweed sources.

For side by side comparisons of output by the top producing countries, you can combine the individual histograms onto a single graph. Or, calculate the percentage of total world production attributable to each country and create a pie chart.

Why might the top producers of brown seaweeds be somewhat different from the top red seaweed producers? Hint: Check out the biology of brown and red seaweeds, where do most of them grow?

Who imports seaweeds?

Which countries import the most seaweeds? Many countries import seaweeds, including the United States. Use TradeData International's report to research who buys the most.

Make a list of the top 5 seaweed-importing countries in the world.

What was the value of seaweed imports into all countries in 2001?

How much seaweed did the US buy in 2001? What proportion of the world's seaweed market did this represent? From which countries does the US buy seaweeds?

Visit the Smithsonian Ocean Planet exhibition website and print the list of the products containing algae. Imagine that you are at a school similar to Bridgeport and have a seaweed aquaculture facility. Pick a type of seaweed that your school might grow, determine what products might come from that seaweed, and research which countries might be interested in importing seaweed from you. Design a marketing campaign to sell for your seaweed.

Seaweed products provide just one example of how chemicals derived from marine organisms have become increasingly important in our lives. The sea's biodiversity and extreme environments continue to attract scientists as they search for new compounds, organisms and biotechnology opportunities. The treasures we can extract from the sea should also heighten our efforts to sustain healthy marine ecosystems and their full complements of marine life.